2013 135i massive turbo leak gets worse

[Revoke]

For about two weeks I experience a substantial loss in power out of the blue. MHD told me I was targeting 16 psi, meanwhile, I would only peak at 10 psi. Drove it for about two weeks, and only tried refitting some connections with no luck. At this time it was not showing codes while behaving normally, despite a massive loss of power and almost no boost until 2500 rpm. I took it into the shop to get the VSFR Charge pipe and intercooler on (not to fix the problem, I already had them and thought it could help) Went in to get new brakes installed as well as replace the harmonic balancer. After receiving the car back and test driving it, it would only peak at 8 psi of boost and make a very loud intake-sucking sound, but not from the intake.

The pedal now feels like a brick and I am driving underwater, the boost feels like it's stuck, a blockage almost. Every time I give it more than 50% throttle for more than 4 seconds, the half-filled check engine light appears. These are the codes I have received.

2906- Suspicion of Leaks between exhaust turbocharger and intake valves. Pops up every single time
2774- air volume, plausibility: Air volume too high.
Only seen once
29d8- Intake air temperature- charge air temperature, comparison: Intake air temperature too high.
Only seen once, on the first scan
290A- Intake air temperature sensor: Multiple fault.
Only seen once, on the first scan

On start-up, it sputters and shakes violently and revs between 400-1000 almost uncontrollably for 10 seconds. Changing between reverse and drive makes the car jerk and sputter slightly like on start-up. Incredibly lurchy, even at higher speeds, the boost feels inconsistent and like there is strong resistance on the pedal and boost. Intake sounds fine, but there is another sucking noise that only shows up around 3000 rpm, it becomes very loud when on the throttle. The last symptom is an almost radio whine sound, like when you leave your radio up all the way with no sound. This was coming from the engine bay. My mechanic also noticed when taking off the oil cap, what seemed like air/pressure was released. I have found nothing loose and have run out of solutions via google. I have tried everything, what can it be, what should I do?

[TWO STEP TEX]

I just had this happen to me. Turned out to be a cracked valve cover. Get it smoke tested and you'll find your leak. I didn't have the assorted noises you have, but it was bucking and wouldn't idle. I unplugged the MAF and it drive ok for about 150 miles but then I had issues with the valvetronic as a result. A flash back to stock using MHD reset the valvetronic motor. Good luck.

[Revoke]

Originally Posted by TWO STEP TEX

I just had this happen to me. Turned out to be a cracked valve cover. Get it smoke tested and you'll find your leak. I didn't have the assorted noises you have, but it was bucking and wouldn't idle. I unplugged the MAF and it drive ok for about 150 miles but then I had issues with the valvetronic as a result. A flash back to stock using MHD reset the valvetronic motor. Good luck.

Had it smoke tested and my mechanic found one leak in the newly installed charge pipe. I was given the VSFR charge pipe with the flanges, and one of the bolts came loose. He fixed that leak and had me test-drive it. The leak seemingly from the charge pipe came back, with the 2906 engine code. The current belief between me and my mechanic is that there are two leaks, one from the valve cover/PCV valve, and one from the charge pipe where the bolt keeps loosening. The charge pipe leak is the one causing the brunt of the issues. Meanwhile, the PCV leak is causing the whining noise as well as causing a 40% boost leak (it was 11psi before the charge pipe leak) with both leaks I am only peaking at 7 PSI. In total I had one leak from the PCV valve when I first brought it in, now I have two leaks after the charge pipe install.